interface IPerson {
  name: string,
  age: number,
  eat(val1: string, val2: number): boolean
}
let person: IPerson = {
  name: '张三',
  age: 12,
  eat(v1, v2) {
    console.log(v1 + v2);
    return false
  }
}
let person3: IPerson = {
  name: '李四',
  age: 18,
  eat(v1, v2) {
    console.log(v1 + v2);
    return false
  }
}
type IStudent = {
  name: string,
  age: number,
  eat(val1: string, val2: number): boolean
}